Re: [Qemu-devel] [PATCH 0/5] Add some tracepoints for clarification of the cause of troubles

[Kazuya Saito]

(2013/03/27 17:45), Paolo Bonzini wrote:>
>>> Wouldn't you get the same information from the command line?
>>
>> I think the information you said is different from what I meant. The
>> information I wanted to know is whether QEMU creates/deletes a device
>> successfully or not.
>
> Failing to create a device will always exit QEMU.  If you cannot assume
> that, you're really in debugging territory and your tools should
> be the "info" monitor commands (info qtree, info pci) or gdb...

That's a good point.

>> We cannot get it from the command line.
>> I was sure I specified a NIC device for the guest, but the Windows
>> guest didn't have it when it booted.  There were two possibilities.  One
>> was QEMU failed to create the NIC device, and the other was QEMU created
>> it successfully and the Windows guest failed to detect it.  Since QEMU
>> output limited message at the moment, it was difficult to prove that
>> it was not QEMU's issue.  I took a coredump of the QEMU and proved
>> the QEMU must have a valid structures for the NIC device.  I believe the
>> tracepoints could have allowed me to figure out where the issue
>> existed a lot faster and easier.
>
> Had you tried "info qtree" or "info pci"?

I didn't try these commands. I tried them just now and it seems to solve
the problem. So I think no need to add the tracepoints I posted.
Thank you for your kindness.

Kazuya